component-dsl/src/main/java/org/apache/aries/component/dsl/internal/RefreshWhenOSGi.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.aries.component.dsl.internal;

import org.apache.aries.component.dsl.OSGi;
import org.apache.aries.component.dsl.OSGiResult;
import org.apache.aries.component.dsl.Publisher;
import org.apache.aries.component.dsl.Refresher;
import org.apache.aries.component.dsl.update.UpdateSelector;
import org.apache.aries.component.dsl.update.UpdateTuple;

import java.util.concurrent.atomic.AtomicReference;
import java.util.function.BiFunction;
import java.util.function.BiPredicate;
import java.util.function.Predicate;

/**
 * @author Carlos Sierra Andrés
 */
public class RefreshWhenOSGi<T> extends OSGiImpl<T> {

    public RefreshWhenOSGi(OSGi<T> program, BiPredicate<UpdateSelector, T> refresher) {
        super((executionContext, op) -> program.run(
            executionContext,
            op.pipe(
                t -> {
                    OSGiResult osgiResult = op.publish(t);

                    return new OSGiResultImpl(
                        osgiResult::close,
                        us -> {
                            if (refresher.test(us, t)) {
                                return true;
                            }

                            return osgiResult.update(us);
                        }
                    );
                }
            )));
    }

}